Display screen or portion thereof with transitional graphical user interface



FIG. 1 is the first image in a sequence of a display screen or portion thereof with transitional graphical user interface showing our new design;

FIG. 2 is the second image thereof;

FIG. 3 is the first image in a sequence showing the claimed design in a different enviroment;

FIG. 4 is the second image thereof;

FIG. 5 is the first image in a sequence showing the claimed design in a different environment; and,

FIG. 6 is the second image thereof.

The dashed broken line perimeter in the drawings illustrates a display screen or portion thereof and forms no part of the claimed design. The remaining dashed broken lines in the drawings illustrate portions of the graphical user interface that form no part of the claimed design.

The stipple shading in FIGS. 2, 4, 6 depicts a contrast of appearance.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1-2, 3-4, and 5-6, respectively. The process or period in which one image transitions into another image forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 